The daily low temperature in Guangzhou, China, varies over time in a periodic way that can be modeled by a trigonometric function. The period of change is exactly
1
11 year. The temperature peaks around July
26
2626 at
7
8
∘
F
78
∘
F78, degrees, F, and has its minimum half a year later at
4
9
∘
F
49
∘
F49, degrees, F. Assuming a year is exactly
365
365365 days, July
26
2626 is
206
365
365
206

start fraction, 206, divided by, 365, end fraction of a year after January
1
11.
Find the formula of the trigonometric function that models the daily low temperature
T
TT in Guangzhou
t
tt years after January
1
11,
2015
20152015. Define the function using radians.